Evaluating the dynamics and electrostatic interactions of folded proteins in implicit solvents

Area of Science:

• Computational chemistry
• Molecular dynamics
• Biophysics

Background:

• Implicit solvent models offer computational efficiency over explicit solvent models for molecular simulations.
• Accurate representation of solvent effects is crucial for predicting protein structure, dynamics, and interactions.
• Evaluating implicit solvent models against explicit water is essential for validating their performance.

Purpose of the Study:

• To assess the accuracy of three implicit solvent models (GBMVII, FACTS, SCPISM) in emulating explicit solvent (TIP3P) effects.
• To compare simulated conformational ensembles, dynamics, and electrostatic interactions of protein domains.
• To determine the suitability of implicit solvent models for different protein architectures.

Main Methods:

• Comparative analysis of implicit (GBMVII, FACTS, SCPISM) and explicit (TIP3P) solvent models.
• Molecular dynamics simulations of Src SH2 and Lyn kinase domains.
• Analysis of root-mean-square (RMS) coordinate deviation, positional fluctuations, and ion-pair distance distributions.

Main Results:

• GBMVII and FACTS accurately reproduced global conformations and ion-pair distributions for the globular Src SH2 domain.
• SCPISM showed distinct ion-pair distributions, indicating inadequate reproduction of electrostatic interactions.
• Implicit solvent models failed to accurately capture solvation, electrostatic interactions, and conformations in the bilobal Lyn kinase domain.

Conclusions:

• FACTS and GBMVII are suitable for modeling local structure and dynamics of small, globular proteins.
• Implicit solvent models exhibit limitations in accurately simulating global conformations and electrostatic interactions in complex, multi-lobal proteins.
• Explicit solvent simulations remain necessary for detailed analysis of intricate protein-solvent interactions in non-globular proteins.